Fast optical switch and its applications in optical communication

ABSTRACT

A fast optical (with or without a photonic crystal) switch is fabricated/constructed, utilizing a phase transition material/Mott insulator, activated by either an electrical pulse (a voltage pulse or a current pulse) and/or a light pulse and/or pulses in terahertz (THz) frequency of a suitable field strength and/or hot electrons. The applications of such a fast optical switch for an on-demand optical add-drop subsystem, integrating with (a) a light slowing/light stopping component (based on metamaterials and/or nanoplasmonic structures) and (b) with or without a wavelength converter are also described.

CROSS REFERENCE OF RELATED APPLICATIONS

The present Patent Application is a continuation-in-part (CIP) of

(a) U.S. Non-Provisional patent application Ser. No. 15/932,404entitled, “FAST OPTICAL SWITCH AND ITS APPLICATIONS IN OPTICALCOMMUNICATION”, filed on Feb. 26, 2018, which resulted in a U.S. Pat.No. 10,185,202, on Jan. 22, 2019,

-   -   wherein (a) is a continuation-in-part (CIP) of (b) U.S.        Non-Provisional patent application Ser. No. 15/731,683 entitled,        “FAST OPTICAL SWITCH AND ITS APPLICATIONS IN OPTICAL        COMMUNICATION”, filed on Jul. 17, 2017 (wherein (b) claims the        benefit of priority from U.S. Provisional Patent Application No.        62/498,246 entitled, “FAST OPTICAL SWITCH AND ITS APPLICATIONS        IN OPTICAL COMMUNICATION”, filed on Dec. 20, 2016), which        resulted in a U.S. Pat. No. 10,009,670 on Jun. 26, 2018,    -   wherein (b) is a continuation-in-part (CIP) of (c)        Non-Provisional patent application Ser. No. 14/756,096 entitled,        “FAST OPTICAL SWITCH AND ITS APPLICATIONS IN OPTICAL        COMMUNICATION”, filed on Aug. 1, 2015, (wherein (c) claims the        benefit of priority from U.S. Provisional Patent Application No.        61/999,601 entitled, “FAST OPTICAL SWITCH”, filed on Aug. 1,        2014), which resulted in a U.S. Pat. No. 9,746,746 on Aug. 29,        2017.

The entire contents of all U.S. Non-Provisional Patent applications andU.S. Provisional Patent applications as listed in the previous paragraphand the filed (patent) Application Data Sheet (ADS) are herebyincorporated by reference.

FIELD OF THE INVENTION

The present invention generally relates to an optical switch and itsapplications in optical communication. In optical communication, anoptical switch enables optical signals to be selectively switched fromone optical fiber/optical circuit to another optical fiber/opticalcircuit. An optical switch can operate by mechanical, electro-optic ormagneto-optic effects.

BACKGROUND OF THE INVENTION

The lithium niobate (LiNbO₃)-LN or (Pb,La)(Zr,Ti)O₃-PLZT or opticalwaveguide-based optical switch is commercially available. The LN/PLZToptical waveguide-based optical switch is a modified balance bridge type1×2 switch, which is composed of (a) a Mach-Zehnder (MZ) deviceintegrated with top electrodes and (b) input-output 3-dB couplers.

The switching speed of an LN optical waveguide-based optical switch isapproximately 100 nanoseconds. Furthermore, it suffers from (a) highvoltage requirements, (b) polarization dependence problems and (c) DCdrift.

The switching speed of a PLZT optical waveguide-based optical switch isapproximately 10 nanoseconds.

The switching speed of a semiconductor optical amplifier (SOA)waveguide-based optical switch is about 1 to 2 nanoseconds. However, thesemiconductor optical amplifier waveguide-based optical switch suffersfrom (a) noise, (b) polarization dependence problems, (c) wavelengthdependence problems and (d) high electrical power consumption.

SUMMARY OF THE INVENTION

In view of the foregoing, three objectives of the present invention are:

-   -   to design and fabricate/construct an optical switch with a        switching speed less than 10 nanoseconds;    -   to reduce (a) noise, (b) polarization dependence problems, (c)        wavelength dependence problems and (d) high electrical power        consumption; and    -   to create a platform to integrate/co-package other optical        components.

Applications for such an optical switch with a switching speed less than10 nanoseconds are:

Optical Communication

-   -   Optical Packet Switches;    -   Optical Add-Drop Subsystem For Optical Packets;    -   Switched Passive Optical Networks (S-PON);

Computing

-   -   High Performance Cloud Computers;    -   High Performance Data Centers; and    -   Optical Interconnects.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A illustrates an embodiment of a fast optical switch in adirectional coupler configuration based on vanadium dioxide (VO₂)ultra-thin-film activated by an electrical pulse just to induce aninsulator-to-metal phase transition (IMT) in vanadium dioxideultra-thin-film.

FIG. 1B illustrates a cross-sectional view of two metal electrodes onvanadium dioxide ultra-thin-film on the left region of the fast opticalswitch in the directional coupler configuration.

FIG. 1C illustrates a cross-sectional view of two metal electrodes onvanadium dioxide ultra-thin-film on the right region of the fast opticalswitch in the directional coupler configuration.

FIG. 1D illustrates an embodiment of three-optical waveguides baseddirectional coupler.

FIG. 1E illustrates an embodiment of a directional coupler utilizing aphotonic crystal.

FIG. 1F illustrates an embodiment of an optical switch, based onMach-Zehnder interferometer.

FIG. 2 illustrates an embodiment of an electronic subsystem to drive thefast optical switch based on vanadium dioxide ultra-thin-film activatedby an electrical pulse.

FIG. 3 illustrates an embodiment of a fast optical switch processor Acomprising the fast optical switch (based on vanadium dioxideultra-thin-film activated by an electrical pulse) in a matrixconfiguration.

FIG. 4 illustrates an embodiment of the fast optical switch based onvanadium dioxide ultra-thin-film activated by a light pulse just toinduce an insulator-to-metal phase transition in vanadium dioxideultra-thin-film.

FIG. 5 illustrates an embodiment of an electronic subsystem to drive thefast optical switch based on vanadium dioxide ultra-thin-film activatedby a light pulse.

FIG. 6 illustrates an embodiment of a fast optical switch processor Bcomprising the fast optical switch (based on vanadium dioxideultra-thin-film activated by a light pulse) in a matrix configuration.

FIG. 7 illustrates an on-demand optical add-drop subsystem (OADS)integrated with the fast optical switch (wherein the fast optical switchis based on vanadium dioxide ultra-thin-film activated by an electricalpulse).

FIG. 8 illustrates an embodiment of an electronic subsystem to drive theon-demand optical add-drop subsystem integrated with the fast opticalswitch (wherein the fast optical switch is based on vanadium dioxideultra-thin-film activated by an electrical pulse).

FIG. 9 illustrates an embodiment of an optical network processor systemA comprising the on-demand optical add-drop subsystem in a matrixconfiguration (wherein the on-demand optical add-drop subsystem furthercomprises the fast optical switch based on vanadium dioxideultra-thin-film activated by an electrical pulse).

FIG. 10 illustrates an on-demand optical add-drop subsystem integratedwith the fast optical switch (wherein the fast optical switch is basedon vanadium dioxide ultra-thin-film activated by a light pulse).

FIG. 11 illustrates an embodiment of an electronic subsystem to drivethe on-demand optical add-drop subsystem integrated with the fastoptical switch (wherein the fast optical switch is based on vanadiumdioxide ultra-thin-film activated by a light pulse).

FIG. 12 illustrates an embodiment of an optical network processor systemB, comprising the on-demand optical add-drop subsystem in a matrixconfiguration (wherein the on-demand optical add-drop subsystem furthercomprises the fast optical switch based on vanadium dioxideultra-thin-film activated by a light pulse).

FIG. 13A illustrates an embodiment of a wavelength converter based on anonlinear four-wave mixing material.

FIG. 13B illustrates another embodiment of a wavelength converter basedon another nonlinear four-wave mixing material.

FIG. 13C illustrates another embodiment of a wavelength converter basedon another nonlinear four-wave mixing material.

FIG. 14 illustrates an on-demand optical add-drop subsystem integratedwith the fast optical switch (wherein the fast optical switch is basedon vanadium dioxide ultra-thin-film activated by an electrical pulse)and a wavelength converter.

FIG. 15 illustrates an embodiment of an electronic subsystem to drivethe on-demand optical add-drop subsystem integrated with the fastoptical switch (wherein the fast optical switch is based on vanadiumdioxide ultra-thin-film activated by an electrical pulse) and thewavelength converter.

FIG. 16 illustrates an embodiment of an advanced optical networkprocessor system C comprising the on-demand optical add-drop subsystemin a matrix configuration (wherein the on-demand optical add-dropsubsystem further comprises the fast optical switch based on vanadiumdioxide ultra-thin-film activated by an electrical pulse) and thewavelength converter.

FIG. 17 illustrates an on-demand optical add-drop subsystem integratedwith the fast optical switch (wherein the fast optical switch is basedon vanadium dioxide ultra-thin-film activated by a light pulse) and thewavelength converter.

FIG. 18 illustrates an embodiment of an electronic subsystem to drivethe on-demand optical add-drop subsystem integrated with the fastoptical switch (wherein the fast optical switch is based on vanadiumdioxide ultra-thin-film activated by a light pulse) and the wavelengthconverter.

FIG. 19 illustrates an embodiment of an advanced optical networkprocessor system D comprising the on-demand optical add-drop subsystemin a matrix configuration (wherein the on-demand optical add-dropsubsystem further comprises the fast optical switch based on vanadiumdioxide ultra-thin-film activated by a light pulse) and the wavelengthconverter.

DETAILED DESCRIPTION OF THE DRAWINGS

Vanadium dioxide is broadly related to phase transition/Mott insulatormaterial. Vanadium dioxide exhibits rapid (less than 10 nanoseconds)insulator-to-metal phase transition upon temperature increase. Vanadiumdioxide shows an abrupt decrease of resistance when applied current orvoltage exceeds a certain threshold value. This is an electricfield-induced rapid phase transition.

The rapid (less than 10 nanoseconds) insulator-to-metal phase transitioncan be utilized in conjunction with a coupled waveguide configuration(e.g., a directional coupler/multi-mode interference (MMI) coupler orMach-Zehnder interferometer) to fabricate/construct a fast opticalswitch.

The operational principle of a directional coupler is evanescent wavecoupling, where two single-mode waveguides come close to each otheralong a coupling length.

The dimension of the coupling length can depend on other parameters(e.g., overall dimension and switching speed of the optical switch).Furthermore, extinction ratio/power transfer ratio can depend on theindex mismatch and the coupling parameters and the state of 120—thevanadium dioxide ultra-thin-film.

FIG. 1A illustrates an embodiment of 100A—a fast optical switch (in thedirectional coupler design) based on 120—the vanadium dioxideultra-thin-film activated by an electrical pulse. The electrical pulsecan be a voltage/current pulse.

100A—the fast optical switch (in the directional coupler design) can befabricated/constructed on a silicon-on-insulator (SOI) substrate.

But, other suitable substrate (e.g., a silicon-on-sapphire (SOS)substrate or a diamond-on-insulator (DOI)) can also be utilized.

An electrical pulse can be a current pulse or a voltage pulse. 120—thevanadium dioxide ultra-thin-film is receiving a voltage pulse or acurrent pulse via two electrodes just to induce an insulator-to-metalphase transition in the vanadium dioxide ultra-thin-film. For example, asquare wave-shaped voltage pulse with a rise time of approximately 10nanoseconds and a fall time of approximately 10 nanoseconds with a pulseduration of 500 nanoseconds can be utilized.

It should be noted that the insulator-to-metal phase transition withcorresponding electrical and optical properties can be with or withoutany change/deformation in lattice structure of the vanadium dioxide.

In FIG. 1A, 100A denotes the fast optical switch and 120 denotesvanadium dioxide ultra-thin-film. 140A denotes the left region and 140Bdenotes the right region. 160A1 denotes the left metal electrode on120—the vanadium dioxide ultra-thin-film (on 140A—the left region) and160A2 denotes the right metal electrode on 120—the vanadium dioxideultra-thin film (on 140A—left region). 160B1 denotes the left metalelectrode on 120—the vanadium dioxide ultra-thin-film (on 140B—the rightregion) and 160B2 denotes the right metal electrode on 120—the vanadiumdioxide ultra-thin-film (on 140B—the right region).

It should be noted that 120—the vanadium dioxide ultra-thin-film canalso be deposited in the curved region other than 140A—the left regionand 140B—the right region.

It should be noted that 120—the vanadium dioxide ultra-thin-film canalso be deposited on an intermediate layer of ultra-thin-film of asemiconductor (e.g., silicon-germanium (Si—Ge)) or insulating material(e.g., aluminum dioxide). The intermediate layer of ultra-thin-film of asemiconductor is generally of same length of 120—the vanadium dioxideultra-thin-film

200—an optical waveguide on 140A—the left region can be based on siliconor silicon nitride or a suitable (optical) low-loss material.

200—the optical waveguide on 140A—the left region can be coupled witheither a one-dimensional (1-D) or a two-dimensional (2-D) photoniccrystal (of air/silica filed holes) generally in the coupling region toslow light propagation to increase light-material interaction. Theone-dimensional or two-dimensional photonic crystal can be modeled by afinite-difference time-domain (FDTD) method (e.g., utilizing MEEP).

The one-dimensional or two-dimensional photonic crystal (generally inthe coupling region) can reduce the length of 120—the vanadium dioxideultra-thin-film and electrical power consumption during opticalswitching.

200—the optical waveguide on 140B—the right region can be based onsilicon or silicon nitride or a suitable (optical) low-loss material.200—the optical waveguide can be coupled with either the one-dimensionalor two-dimensional photonic crystal (generally in the coupling region)to slow light propagation.

It should be noted that 200—the optical waveguide on 140A—the leftregion can have different vertical height/thickness/depth with respectto 200—the optical waveguide on 140A—the right region.

Furthermore, it should be noted that 200—the optical waveguide on140A—the left region can have different horizontal width with respect to200—the optical waveguide on 140A—the right region.

It should be noted that in some design applications, 120—the vanadiumdioxide ultra-thin film is not on 140A—the left region and 140B—theright region, rather suitably on a separate optical waveguide in the gapbetween the 140A—the left region and 140B—the right region to reduceoptical loss and cross-talk.

This separate optical waveguide in the gap between the 140A—the leftregion and 140B—the right region can have different verticalheight/thickness/depth and/or different horizontal width.

This separate optical waveguide in the gap between the 140A—the leftregion and 140B—the right region can be coupled with either theone-dimensional or two-dimensional photonic crystal (of air/silica filedholes) generally in the coupling region to slow light propagation toincrease light-material interaction.

120—the vanadium dioxide ultra-thin-film can be a single section ormultiple sections.

120—the vanadium dioxide ultra-thin-film can also comprise gratings ofthe vanadium dioxide material.

The vertical height/thickness/depth of 120—the vanadium dioxideultra-thin-film is less than 1 micron. In many configurations, itgenerally ranges from 0.1 microns to 0.5 microns.

120—the vanadium dioxide ultra-thin-film is approximately in the rangeof 0.01 microns² to 2 microns² in area on 140A—the left region.

120—the vanadium dioxide ultra-thin-film is approximately in the rangeof 0.01 microns² to 2 microns² in area on 140B—the right region.

It should be noted that by nanoscaling the area (or even volume) of120—the vanadium dioxide ultra-thin-film in the range of approximately0.01 microns², an ultra-fast (approximately 1-2 nanoseconds) opticalswitch (activated by an electrical pulse) can be realized, provided allparameters such as insertion loss, return loss, cross-talk andextinction ratio are optimized.

The ridge (horizontal) width and ridge depth of 200—the opticalwaveguide in 140A—the left region are approximately in the range of 0.2microns to 5 microns and 0.1 microns to 1 micron respectively.Furthermore, both ends of 200—the optical waveguide in 140A—the leftregion can be tapered out gradually (and also antireflection coated atboth ends of 200—the optical waveguide in 140A—the left region) foroptical mode matching for a higher percentage of single-mode opticalfiber coupling. Additionally, both ends of 200—the optical waveguide in140A—the left region can be fabricated/constructed with verticallycoupled gratings for optical mode matching for a higher percentage ofsingle-mode optical fiber coupling.

The ridge (horizontal) width and ridge depth of 200—the opticalwaveguide in 140B—the right region are approximately in the range of 0.2microns to 5 microns and 0.1 microns to 1 micron respectively.Furthermore, both ends of 200—the optical waveguide in 140B—the rightregion can be tapered out gradually (and antireflection coated at bothends of 200—the optical waveguide in 140B—the right region) for opticalmode matching for a higher percentage of single-mode optical fibercoupling.

The distance between 140A—the left region and 140B—the right region isless than 5 microns.

100A—the fast optical switch is a 2×2 fast optical switch with twoinputs and two outputs.

The fabrication process of 100A—the fast optical switch (in adirectional coupler design) is outlined below, when 120—the vanadiumdioxide is an ultra-thin-film.

Deposition of 120—the vanadium dioxide ultra-thin-film (polycrystalline)of less than 0.5 microns in thickness by radio frequency (RF) magnetronsputtering from vanadium dioxide target under argon gas flow(approximately 100 sccm) and oxygen gas flow (approximately 10 sccm) atapproximately in the range of 300 degrees centigrade to 550 degreescentigrade on a silicon-on-insulator substrate, having a silicon layerthickness of approximately in the range of 0.1 microns to 0.5 microns,having an insulator (silicon dioxide) layer thickness of approximatelyin the range of 0.25 microns to 3 microns, having a substrate thicknessof approximately in the range of 350 microns to 675 microns.

Alternatively, direct current (DC) magnetron sputtering from vanadiumtarget under a suitable argon gas flow rate and oxygen gas flow rate atapproximately in the range of 300 degrees centigrade to 550 degreescentigrade can be utilized to deposit 120—the vanadium dioxideultra-thin-film.

Alternatively, electron beam evaporation or laser-assisted electron beamevaporation from a high purity form of divanadium tetroxide (V₂O₄)powder can be utilized to deposit 120—the vanadium dioxideultra-thin-film.

Alternatively, a low-temperature atomic layer epitaxial (ALE) processcan be utilized to deposit 120—the vanadium dioxide ultra-thin-film.

Alternatively, a low-temperature molecular beam epitaxy (MBE) processcan be utilized to deposit 120—the vanadium dioxide ultra-thin-film.

Additionally, a thermal annealing/rapid thermal annealing (RTA) processunder a suitable argon gas flow rate and oxygen gas flow rate can beutilized to enhance grain size and correct any oxygen deficiency of120—the vanadium dioxide ultra-thin-film (polycrystalline).

Additionally, an ultra-thin-film aluminum oxide in the range of 0.010microns to 0.015 microns in thickness as a buffer layer prior to anydeposition of 120—the vanadium dioxide ultra-thin-film can lead toimproved crystallinity and textures in 120—the vanadium dioxideultra-thin-film.

Additionally, an ultra-thin-film aluminum oxide in the range of 0.010microns to 0.015 microns in thickness as a protection layer after to anydeposition of 120—the vanadium dioxide ultra-thin-film can lead toimproved surface protection of 120—the vanadium dioxide ultra-thin-film.

120—the vanadium dioxide ultra-thin-film can be stoichiometric undopedvanadium dioxide or doped (e.g., germanium or tungsten) vanadiumdioxide, wherein doping can change (a) the thermal conductivity, (b)phase transition temperature, or (c) ON/OFF ratio/profile of electricalconductivity of 120—the vanadium dioxide ultra-thin-film.

120—the vanadium dioxide ultra-thin-film can be replaced by anotherphase transition material/Mott insulator material (e.g., niobium oxide(niobium monoxide NbO/niobium dioxide NbO₂/niobium pentoxide Nb₂O₅).

120—the vanadium dioxide ultra-thin-film can be replaced by a phasechange material (e.g., Ge₂Sb₂Te₅ (GST) or Ge₂Sb₂Se₄Te₁ (GSST)), whereinthe phase can be changed by applying a short burst of heat, suppliedelectrically and/or optically.

Alternatively, 120—the vanadium dioxide ultra-thin-film can be replacedby an ultra-fast switching phase change material amorphousAg₄In₃Sb₆₇Te₂₆ (AIST), wherein the phase can be changed in an extremelyshort time scale (sub-picoseconds) by applying short bursts of heat,supplied electrically and/or optically or by pulses in terahertzfrequency of a suitable field strength.

A few picoseconds duration electric pulses of a suitable electric fieldstrength or a few picoseconds duration of pulses in terahertz frequencyof a suitable field strength can be utilized to excite amorphousAg₄In₃Sb₆₇Te₂₆ for threshold switching. Field-dependent reversiblechanges in conductivity/pulse-driven crystallization/threshold switchingcan be observed in sub-picoseconds time scale.

Ultra-short (e.g., 1 picosecond) and terahertz pulses of a suitablefield strength across a pair of nano antennas (e.g., metal nanoantennas) can create an electric field induced phase change in a phasechange material with limited joule heating.

Reactive ion or ion etching of 120—the vanadium dioxide ultra-thin-filmand the silicon layer (of the silicon-on-insulator substrate) toapproximately in the range of 0.2 microns to 5 microns in horizontalwidth and approximately in the range of 0.1 microns to 1 micron in depthto form 200—an optical waveguide in 140A—the left region and itscontinued curved structure can be realized. Furthermore, both ends of200—the optical waveguide can be tapered out gradually (and alsoantireflection coated at both ends of 200—the optical waveguide in140A—the left region) for optical mode matching for a higher percentageof single-mode optical fiber coupling. Additionally, both ends of200—the optical waveguide in 140A—the left region can befabricated/constructed with vertically coupled gratings for optical modematching for a higher percentage of single-mode optical fiber coupling.

Similarly, reactive ion or ion etching of 120—the vanadium dioxideultra-thin-film and the silicon layer (of the silicon-on-insulatorsubstrate) to approximately in the range of 0.2 microns to 5 microns inhorizontal width and approximately in the range of 0.1 microns to 1micron in depth to form 200—an optical waveguide in 140B—the rightregion and its continued curved structure can be realized. Furthermore,both ends of 200—the optical waveguide can be tapered out gradually (andalso antireflection coated at both ends of 200—the optical waveguide in140B—the right region) for optical mode matching for a higher percentageof single-mode optical fiber coupling. Additionally, both ends of200—the optical waveguide in 140A—the left region can befabricated/constructed with vertically coupled gratings for optical modematching for a higher percentage of single-mode optical fiber coupling.

Electron beam lithography and lift off of:

-   -   a first metal layer of titanium/chromium/palladium and a second        metal layer of gold for 160A1—the left metal electrode and        160A2—the right metal electrode on 120—the vanadium dioxide        ultra-thin-film (on 140A—the left region); and    -   the first metal layer of titanium/chromium/palladium and the        second metal layer of gold for 160B1—the left metal electrode        and 160B2—the right metal electrode on 120—the vanadium dioxide        ultra-thin-film (on 140B—the right region).

The thickness of the first metal layer of titanium/chromium/palladium isapproximately in the range of 0.010 microns to 0.02 microns.

The thickness of the second metal layer of gold is approximately in therange of 0.25 microns to 0.35 microns. It should be noted that thicknessof the second metal layer of gold can be optimized to reduce stress on120—the vanadium dioxide ultra-thin-film in mitigatingstability/reliability issues with 120—the vanadium dioxideultra-thin-film.

Alternatively, the first metal can be a combination of an adhesionpromoting metal (e.g., titanium/chromium) in the range of 0.005 micronsin thickness and a ultra-thin metal (e.g., gold) in the range of 0.010microns in thickness, wherein the said first metal can be fabricated asnansocaled island of about 50 nanometers in diameter. The first metalcan be electrically coupled with two metal electrodes of the secondmetal of an adhesion promoting metal (e.g., titanium) in the range of0.015 microns in thickness and a ultra-thin metal (e.g., aluminum) inthe range of 0.25 to 0.35 microns in thickness, wherein the two metalelectrodes are separated by a nanoscaled gap (e.g., 20 nanometers to 100nanometers). This arrangement can inject hot electrons into 120—thevanadium dioxide ultra-thin-film for ultrafast (less than 1-2nanoseconds) optical switching. Alternatively, hot electrons can beinjected into 120—the vanadium dioxide ultra-thin-film for ultrafast(less than 1-2 nanoseconds) optical switching by photo-excitation.

Furthermore, a high dielectric constant insulator (e.g., hafniumsilicate, zirconium silicate, hafnium dioxide and zirconium dioxide) ofapproximate thickness of 0.005 microns can be fabricated/constructed toelectrically insulate two electrodes on 140A—the left region and twoelectrodes on 140B—the right region from 120—the vanadium dioxideultra-thin-film.

In some design applications, indium tin oxide (ITO) (with refractiveindex between 1.2 and 1.8) as transparent electrodes can be considered.

Alternatively, a parallel plate capacitor with an air gap can beutilized instead of the high dielectric constant insulator. When avoltage pulse is applied across electrodes on a parallel platecapacitor, an electric field due to the voltage pulse is establishedacross the air gap and a smaller electric field due to the voltage pulseis then coupled with 120—the vanadium dioxide ultra-thin-film.

Additionally, 100A—the optical switch can be coupled with an opticalfilter or a ring resonator or a laser (including utilizing monolithicintegration of a device quality III-V material on silicon u-grooves ofabout 100 nanometers pitch by hetero-epitaxy).

Additionally, 100A—the optical switch can be coupled with one or moresemiconductor amplifiers/optical attenuators to compensate for anoptical loss/gain respectively, which can be actively controlledutilizing one or more waveguide photodiodes. Furthermore, one or moresemiconductor amplifiers can be replaced by one or more erbium dopedwaveguide amplifiers.

100A—the optical switch can be maintained at a suitable temperature by athermoelectric cooler (TEC).

It should be noted that the above fabrication steps can be modified in anumber of ways (e.g., self alignment and/or planarization) for notheating adjacent silicon, as heating adjacent silicon can undesirablyslow the switching speed of 100A—the optical switch.

100A—the optical switch can be flip-chip mounted on a nanoscaled finarray and/or a heat spreader (e.g., a synthetic diamond heatspreader/single crystal boron arsenide (BAs) heat spreader) to spreadaccumulated heat for faster OFF switching time.

The nanoscaled fin array is an ordered array of nanoscaled metal (e.g.,aluminum/gold) pillars/posts within a thermally conducting layer (e.g.,alumina).

Dicing, testing and single-mode optical fiber pigtailing of 100A—thefast optical switch chips can be realized.

Connecting the tested/pigtailed good 100A—the fast optical switch chipsonto a printed electronics circuit board can be realized.

In FIG. 1A, 180A denotes a first input port of an input wavelength and180B denotes a second input port of an input wavelength. 200 denotes theoptical waveguide. The input wavelength at 180A—the first input port canexit via 220A—an output exit, when 140A—the left region comprising120—the vanadium dioxide ultra-thin-film is not electrically activatedby an electrical pulse on both 160A1—the left metal electrode and160A2—the right metal electrode on 120—the vanadium dioxideultra-thin-film (on 140A—the left region).

However, the input wavelength at 180A—the first input port can exit via220B—an output exit, when 140A—the left region comprising 120—thevanadium dioxide ultra-thin-film is electrically activated by anelectrical pulse on both 160A1—the left metal electrode and 160A2—theright metal electrode on 120—the vanadium dioxide ultra-thin-film (on140A—the left region) just to induce an insulator-to-metal phasetransition in 120—the vanadium dioxide ultra-thin-film.

Similarly, the input wavelength at 180B—the second input port can exitvia 200A—an output exit, when 140B—the right region comprising the120—the vanadium dioxide ultra-thin-film is electrically activated by anelectrical pulse on both 160B1—the left metal electrode and 160B2—theright metal electrode on 120—the vanadium dioxide ultra-thin-film (on140B—the right region) just to induce an insulator-to-metal phasetransition in 120—the vanadium dioxide ultra-thin-film.

120—the vanadium dioxide ultra-thin-film is receiving an electricalpulse just to induce an insulator-to-metal phase transition in 120—thevanadium dioxide ultra-thin-film.

Other coupler designs (e.g., multimode interference or Mach-Zehnderinterferometer) can be realized by using an electrical pulse forinducing an insulator-to-metal phase transition in 120—the vanadiumdioxide ultra-thin-film.

However, an insulator-to-metal phase transition can be with a change inlattice structure or without a change in lattice structure (without achange in lattice structure can minimize any joule heating and thus, canenable an ultrafast optical switch even in picoseconds/femtoseconds).

It should be noted that a cluster of vanadium dioxide particles (lessthan 0.5 microns in diameter) embedded in an ultra-thin-film of apolymeric material or in a mesh of metal nanowires can be utilizedinstead of 120—the vanadium dioxide ultra-thin-film infabricating/constructing 100A—the fast optical switch activated by anelectrical pulse. The polymeric material can be either conducting,semiconducting or non-conducting. Thus, vanadium dioxide particles (lessthan 0.5 microns in diameter) embedded in an ultra-thin-film of apolymeric material or in a mesh of metal nanowires can receive anelectrical pulse just to induce an insulator-to-metal phase transitionin the cluster of vanadium dioxide particles (less than 0.5 microns indiameter).

Furthermore, 120—the vanadium dioxide ultra-thin-film can be replaced bya monolayer(s) of a two-dimensional material (e.g., germanene, graphene,phosphorene, silicene and stanene) first, then followed by the vanadiumdioxide ultra-thin-film last (option 1) or the vanadium dioxideultra-thin-film first, then followed by a monolayer(s) of atwo-dimensional material last (option 2) or a monolayer(s) of atwo-dimensional material first then followed by the vanadium dioxideultra-thin-film in the middle, then followed by a monolayer(s) of atwo-dimensional material last (option 3). Integration of a monolayer(s)of a two-dimensional material can enable faster heat dissipation and/orelectronic properties of the entire stacked materials for faster offswitching time. The total vertical height/thickness/depth of thevanadium dioxide ultra-thin-film and a monolayer(s) of a two-dimensionalmaterial is still less than 1 micron. It should be noted that thetwo-dimensional material and/or vanadium dioxide can be in the form aquantum dot(s). It should be noted that vanadium dioxide can also bedoped or undoped, as described in previous paragraphs.

FIG. 1B illustrates a cross-sectional view of 160A1—the left metalelectrode and 160A′2—the right metal electrode on 120—the vanadiumdioxide ultra-thin-film (on 140A—the left region), wherein 120—thevanadium dioxide ultra-thin-film is on the silicon layer of thesilicon-on-insulator substrate. 200 denotes the optical waveguide.

FIG. 1C illustrates a cross-sectional view of 160B1—the left metalelectrode and 160B2—the right metal electrode on 120—the vanadiumdioxide ultra-thin-film (140B—the right region), wherein 120—thevanadium dioxide ultra-thin-film is on the silicon layer of thesilicon-on-insulator substrate. 200 denotes the optical waveguide.

Furthermore, the silicon layer of the silicon-on-insulator substrate canbe reactive ion or ion etched up to the silica layer of thesilicon-on-insulator substrate.

FIG. 1D illustrates an embodiment of three-optical waveguides baseddirectional coupler, wherein the middle optical waveguide (including120—the vanadium dioxide ultra-thin-film with electrical bias electrodes(electrical bias electrodes are not shown in the FIG. 1D) controls theoptical coupling between the first optical waveguide and third opticalwaveguide.

FIG. 1E illustrates an embodiment of a directional coupler utilizing aphotonic crystal.

The size of a hole and periodicity of a photonic crystal can besimulated for a particular application, utilizing MEEP software program.

The ratio of a hole radius to a lattice constant (of a photonic crystal)can range from 0.3 to 0.4. Furthermore, a photonic crystal can be eithersymmetrically or asymmetrically designed and filled with silicon dioxide(rather than air holes).

FIG. 1F illustrates an embodiment of an optical switch, based onMach-Zehnder interferometer (including 120—the vanadium dioxideultra-thin-film with electrical bias electrodes (electrical biaselectrodes are not shown in the FIG. 1F) on each arm of the Mach-Zehnderinterferometer. The Mach-Zehnder interferometer includes an input 3-dBcoupler and an output 3-dB coupler.

Metamaterials and/or nanoplasmonic structures endowed with specialnegative refractive index properties, surrounded by normal materialswith positive refractive index properties, as a light (or opticalsignal(s)) slowing/light (or optical signal(s)) buffering component canslow (even stop) light/optical signal(s) at either input or output of100A—the fast optical switch (based on 120—the vanadium dioxideultra-thin-film activated by an electrical pulse) for optical processingwithout any optical-electrical-optical (O-E-O) conversion to read headerinformation of an optical (internet) packet optically. Thus, this canenable an all-optical network.

Furthermore, the wavelength or frequency or color of a composite light(or composite optical signal(s)) can slow (even stop) at differentspatial points (of metamaterials and/or nanoplasmonic structures endowedwith special negative refractive index properties, surrounded by normalmaterials with positive refractive index properties) to have a trappedeffect.

Furthermore, a nanowire of a nonlinear material (e.g., cadmium sulfide)wrapped by a dielectric material, then wrapped by a silver shell ateither input or output of 100A—the fast optical switch (based on 120—thevanadium dioxide ultra-thin-film activated by an electrical pulse) canchange the wavelength or frequency or color of light that passes throughit. By confining light within the nonlinear material rather than at theinterface between the nonlinear material and the silver shell, lightintensity can be maximized, while changing the wavelength or frequencyor color of light that passes through it.

Additionally, by applying an electric field across a nanosccaled ring ofa nonlinear material (e.g., cadmium sulfide), mixing of optical signalsat high on or off ratio can be obtained. Such mixing of optical signalsat high on or off ratio can act as an optical transistor.

FIG. 2 illustrates an embodiment of 300A—an electronic subsystem todrive 100A—the fast optical switch (based on 120—the vanadium dioxideultra-thin-film activated by an electrical pulse).

In FIG. 2, 240 denotes an external controller, 260 denotes amicroprocessor/field programmable gate array (FPGA) and 280A denotes adrive electronics unit/module for 100A—the fast optical switch.

300A—the electronic subsystem integrates 240, 260 and 280A. 300A—theelectronic subsystem is to drive 100A—the fast optical switch.

240—the external controller can communicate serially with 260—themicroprocessor/field programmable gate array.

FIG. 3 illustrates an embodiment of 400A—a fast optical switch processorA, comprising 100A—the fast optical switch in a matrix configuration(wherein 100A—the fast optical switch is based on 120—the vanadiumdioxide ultra-thin-film activated by an electrical pulse just to inducean insulator-to-metal phase transition in 120—the vanadium dioxideultra-thin-film).

In FIG. 3, 400A denotes a fast optical switch processor A; 200 denotesthe optical waveguide; 320 denotes an input single-mode optical fiberarray; 300A denotes the electronic subsystem to drive 100A—the fastoptical switch (based on 120—the vanadium dioxide ultra-thin filmactivated by an electrical pulse); 340 denotes a thermoelectric coolerto maintain 400A—the fast optical switch processor A at a specifiedtemperature; 360 denotes a heat sink and 380 denotes an outputsingle-mode optical fiber array.

Thus, 400A—the fast optical switch processor A can switch a wavelengthfrom any input fiber to any output fiber in less than 10 nanoseconds.

FIG. 4 illustrates an embodiment of 100B—a fast optical switch (in thedirectional coupler configuration) based on the 120—the vanadium dioxideultra-thin-film, activated by a light pulse, on a silicon-on-insulatorsubstrate.

In FIG. 4, 100B denotes a fast optical switch, 120 denotes vanadiumdioxide ultra-thin-film. 140A denotes the left region and 140B denotesthe right region.

The vertical height/thickness/depth of 120—the vanadium dioxideultra-thin-film is less than 0.5 microns.

120—the vanadium dioxide ultra-thin-film is approximately in the rangeof 0.01 microns² to 2 microns² in area on 140A—the left region.

120—the vanadium dioxide ultra-thin-film is approximately in the rangeof 0.01 microns² to 2 microns² in area on 140B—the right region.

It should be noted that by nanoscaling the area of 120—the vanadiumdioxide ultra-thin-film in the range of approximately 0.01 microns², anultrafast (approximately 1-2 nanoseconds) optical switch (activated by alight pulse or pulses in terahertz frequency of a suitable fieldstrength) can be realized.

Ultra-short (e.g., 1 picosecond) and terahertz pulses of a suitablefield strength across a pair of nano antennas (e.g., metal nanoantennas) can create an electric field induced insulator to metal phasetransition in a phase transition material with limited joule heating.

Also, utilizing the insulator-to-metal phase transition without anychange/deformation in lattice structure of the vanadium dioxide, anultra-fast (approximately 0.1 nanoseconds) optical switch (activated bya light pulse or pulses in terahertz frequency of a suitable fieldstrength) can be realized by eliminating any nanoscaled joule heating.

The ridge (horizontal) width and ridge depth of 200—the opticalwaveguide in 140A—the left region are approximately in the range of 0.2microns to 5 microns and 0.1 microns to 1 micron respectively.Furthermore, both ends of 200—the optical waveguide in 140A—the leftregion can be tapered out gradually (and also antireflection coated atboth ends of 200—the optical waveguide in 140A—the left region) foroptical mode matching for a higher percentage of single-mode opticalfiber coupling. Additionally, both ends of 200—the optical waveguide in140A—the left region can be fabricated/constructed with verticallycoupled gratings for optical mode matching for a higher percentage ofsingle-mode optical fiber coupling.

The ridge (horizontal) width and ridge depth of 200—the opticalwaveguide in 140B—the right region are approximately in the range of 0.2microns to 5 microns and 0.1 microns to 1 micron respectively.Furthermore, both ends of 200—the optical waveguide in 140B—the rightregion can be tapered out gradually (and antireflection coated at bothends of 200—the optical waveguide in 140B—the right region) for opticalmode matching for a higher percentage of single-mode optical fibercoupling.

The distance between 140A—the left region and 140B—the right region isless than 5 microns.

100B—the fast optical switch is a 2×2 fast optical switch with twoinputs and two outputs.

In FIG. 4, 180A denotes the first input port of the input wavelength.The input wavelength at 180A—the first input port can exit via 220A—theoutput exit, when 140A—the left region comprising 120—the vanadiumdioxide ultra-thin-film is not optically activated by a light pulse on120—the vanadium dioxide ultra-thin-film on 140A—the left region.

However, the input wavelength at 180A—the first input port can exit via220B—the output exit, when 140A—the left region comprising 120—thevanadium dioxide ultra-thin-film is optically activated by a light pulse(e.g., a light pulse from a mode locked semiconductor laser) on 120—thevanadium dioxide ultra-thin-film on 140A—the left region just to inducean insulator-to-metal phase transition on 120—the vanadium dioxideultra-thin-film.

Similarly, the input wavelength at 180B—the second input port can exitvia 200A—the output exit, when 140B—the right region comprising 120—thevanadium dioxide ultra-thin-film is optically activated by a light pulse(e.g., a light pulse from a mode locked semiconductor laser) on 120—thevanadium dioxide ultra-thin-film on 140B—the right region just to inducean insulator-to-metal phase transition on 120—the vanadium dioxideultra-thin-film.

The insulator-to-metal phase transition with corresponding electricaland optical properties can be with or without any change/deformation inlattice structure of transition.

The intensity (optical power per unit area) of the light pulse isapproximately in the range of 0.1 mJ/cm² to 50 mJ/cm². The pulse widthof the light pulse is approximately in the range of 0.001 nanoseconds to0.1 nanoseconds.

Furthermore, a sub-femtosecond near infrared (NIR) laser pulse or aterahertz pulse of suitable field strength can enable theinsulator-to-metal transition in 120—the vanadium dioxideultra-thin-film in about 20-30 picoseconds.

The 120—the vanadium dioxide ultra-thin-film is receiving a light pulsejust to induce an insulator-to-metal phase transition in 120—thevanadium dioxide ultra-thin-film.

The light pulse can propagate through 460—an optical waveguide and befocused by 480—a lens onto 120—the vanadium dioxide ultra-thin-film.

However, either a focusing up configuration or a focusing downconfiguration is possible

460—the optical waveguide is fabricated/constructed on 440—a bufferlayer, wherein 440—the buffer layer is fabricated/constructed on 420—asuitable substrate (e.g., a silicon-on-insulator substrate).

One pulsed light source is required for 140A—the left region comprising120—the vanadium dioxide ultra-thin-film and another pulsed light sourceis required for 140B—the right region; comprising 120—the vanadiumdioxide ultra-thin-film.

Generally blue-green wavelength vertical cavity semiconductor laser canbe used for the light pulse. Furthermore, 480—a metamaterial-based lenscan be utilized for focusing of the light pulse below the diffractionlimit.

Other coupler designs (e.g., multimode interference or Mach-Zehnderinterferometer) can be realized by a light pulse for just inducing aninsulator-to-metal phase transition in 120—the vanadium dioxideultra-thin-film.

In some design applications, the insulator-to-metal phase transitionwith corresponding electrical and optical properties in 120—the vanadiumdioxide ultra-thin-film can be realized by both light pulse andelectrical pulse.

In some design applications, the insulator-to-metal phase transitionwith corresponding electrical and optical properties in 120—the vanadiumdioxide ultra-thin-film can be realized by pulses in terahertz frequencyof a suitable field strength.

It should be noted that a cluster of vanadium dioxide particles (lessthan 0.5 microns in diameter) embedded in an ultra-thin-film ofpolymeric material or in a mesh of metal nanowires can be utilized,instead of 120—the vanadium dioxide ultra-thin-film infabricating/constructing 100A—the fast optical switch; activated by alight pulse. The polymeric material can be either conducting,semiconducting or non-conducting. Thus, vanadium dioxide particles (lessthan 0.5 microns in diameter) embedded in an ultra-thin-film ofpolymeric material or in a mesh of metal nanowires can receive a lightpulse just to induce an insulator-to-metal phase transition in thecluster of vanadium dioxide particles (less than 0.5 microns indiameter).

Furthermore, 120—the vanadium dioxide ultra-thin-film can be replaced bya monolayer(s) of a two-dimensional material (e.g., germanene, graphene,phosphorene, silicene and stanene) first, followed by the vanadiumdioxide ultra-thin-film last (option 1) or the vanadium dioxideultra-thin-film first, followed by a monolayer(s) of a two-dimensionalmaterial last (option 2) or a monolayer(s) of a two-dimensional materialfirst, followed by the vanadium dioxide ultra-thin-film in the middle,followed by a monolayer(s) of a two-dimensional material last (option3). Integration of a monolayer(s) of a two-dimensional material canenable faster heat dissipation and/or electronic properties of theentire stacked materials for faster off switching time. The totalvertical height/thickness/depth of the vanadium dioxide ultra-thin-filmand a monolayer(s) of a two-dimensional material are less than 0.15microns. It should be noted that the two-dimensional material and/orvanadium dioxide can be in the form a quantum dot(s). It should be notedthat vanadium dioxide can also be doped, as described in previousparagraphs.

Metamaterials and/or nanoplasmonic structures endowed with specialnegative refractive index properties, surrounded by normal materialswith positive refractive index properties, as a light (or opticalsignal(s)) slowing/light (or optical signal(s)) buffering component canslow (even stop) light/optical signal(s) at either input or output of100B—the fast optical switch (based on 120—the vanadium dioxide,ultra-thin-film activated by a light pulse) for optical processingwithout any optical-electrical-optical (O-E-O) conversion to read headerinformation of an optical (internet) packet optically. Thus, this canenable an all-optical network. Furthermore, the wavelength or frequencyor color of a composite light (or composite optical signal(s)) can slow(even stop) at different spatial points (of metamaterials and/ornanoplasmonic structures endowed with special negative refractive indexproperties, surrounded by normal materials with positive refractiveindex properties) to have a trapped effect.

Furthermore, a nanowire of a nonlinear material (e.g., cadmium sulfide)wrapped by a dielectric material, then wrapped by a silver shell ateither input or output of 100B—the fast optical switch (based on 120—thevanadium dioxide ultra-thin-film activated by a light pulse) can changethe wavelength or frequency or color of light that passes through it. Byconfining light within the nonlinear material rather than at theinterface between the nonlinear material and the silver shell, lightintensity can be maximized, while changing the wavelength or frequencyor color of light that passes through it.

Additionally, by applying an electric field across a nanosccaled ring ofa nonlinear material (e.g., cadmium sulfide), mixing of optical signalsat high on or off ratio can be obtained. Such mixing of optical signalsat high on or off ratio can act as an optical transistor.

FIG. 5 illustrates an embodiment of 300B—an electronic subsystem todrive 100B—the fast optical switch (based on 120—the vanadium dioxideultra-thin-film activated by a light pulse).

In FIG. 5, 240 denotes the external controller, 260 denotes themicroprocessor/field programmable gate array, and 280B denotes a driveelectronics unit/module for 100B—the fast optical switch (based on120—the vanadium dioxide, ultra-thin-film activated by a light pulse).

300B—the electronic subsystem integrates 240, 260 and 280B. 300B—theelectronic subsystem to drive 100B—the fast optical switch (based on120—the vanadium dioxide ultra-thin-film activated by a light pulse).

240—the external controller can communicate serially with 260—themicroprocessor/field programmable gate array.

FIG. 6 illustrates an embodiment of 400B—a fast optical switch processorB, comprising 100B—the fast optical switch in a matrix configuration(wherein 100B—the fast optical switch is based on 120—the vanadiumdioxide ultra-thin-film activated by a light pulse).

In FIG. 6, 400B denotes a fast optical switch processor B; 200 denotesthe optical waveguide; 320 denotes the input single-mode optical fiberarray; 300B denotes the electronic subsystem to drive 100B—the fastoptical switch (based on 120—the vanadium dioxide ultra-thin-filmactivated by a light pulse); 340 denotes the thermoelectric cooler tomaintain 400B—the optical switch processor B at a specified temperature;360 denotes the heat sink, and 380 denotes the output single-modeoptical fiber array.

Thus, 400B—the fast optical switch processor B can switch a wavelengthfrom any input fiber to any output fiber in less than 10 nanoseconds.

FIG. 7 illustrates 660A—an on-demand optical add-drop subsystemintegrated with 100A—the fast optical switch (wherein 100A—the fastoptical switch is based on 120—the vanadium dioxide ultra-thin-filmactivated by an electrical pulse).

In FIG. 7 , all input wavelengths from 320—an input optical fiber can betransmitted via 200A—an optical waveguide and amplified by 500—an erbiumdoped waveguide amplifier (EDWA) integrated with a 980-nm pump laser,tapped by 520—a tap coupler to measure wavelengths by 540—aspectrophotometer. A few wavelengths can proceed to 560A/560B/560C—afirst wavelength demultiplexer 1 and then exit to the drop ports. Otherexpress wavelengths can proceed to 560A/560B/560C—a second wavelengthdemultiplexer 2 for demultiplexing then as selective inputs to 100A—thefast optical switch.

It should be noted that a semiconductor optical amplifier can beutilized instead of 500—the erbium doped waveguide amplifier integratedwith a 980-nm pump laser 500.

It should be noted that arrayed waveguide gratings (AWG) basedwavelength multiplexers/demultiplexers can also be utilized.

560A denotes a fixed (wavelength) demultiplexer, 560B denotes a(wavelength) tunable demultiplexer and 560C denotes a (wavelength)tunable one-dimensional photonic crystal-based demultiplexer.

An array of rapidly wavelength tunable lasers can provide a set of newwavelengths to add ports. The output (wavelengths) of 560A/560B/560C—thesecond wavelength demultiplexer 2 and these newly added wavelengths canbe switched by an array of 100As—the fast optical switches.

Switched wavelengths from 100As—the fast optical switches can bemodulated by 580 s-optical modulators (e.g., silicontraveling-waveguide/graphene-on-silicon optical modulators). 580—theoptical modulator can include a (wafer bonded) nanoscaled modulator oflithium niobate.

The optical power output of 580—the optical modulator can be controlledby 500—the erbium doped waveguide amplifier integrated with a 980-nmpump laser, 600—a variable optical attenuator (VOA) (e.g., a PLZT-basedvariable optical attenuator) and 620—a photodiode.

The modulated wavelengths (or modulated optical signals) can beindependently controlled at a specified optical power and thenmultiplexed by 640A/640B/640C—a multiplexer. Thus, independent controlof each wavelength can enable an approximately flat optical power curvefor all output wavelengths at 380—an output optical fiber.

640A denotes a fixed (wavelength) multiplexer, 640B denotes a(wavelength) tunable multiplexer and 640C denotes a (wavelength) tunableone-dimensional photonic crystal-based multiplexer.

A wavelength tunable multiplexer/demultiplexer includes a controlcircuit and one or more controls such as heaters thermally coupledand/or refractive index changing electrical paths electrically coupledto waveguides of the multiplexer/demultiplexer.

The control circuit is in signal communication with one or more controlsand also includes a microprocessor/field programmable gate array coupledwith an electronic memory component. The control circuit receives anidentification signal and adjusts the control in response to theidentification signal and based on parameter values stored in theelectronic memory component.

Alternatively, a voltage tunable multiplexer/demultiplexer can berealized when the material composition of the multiplexer/demultiplexeris a crystalline semiconductor (e.g., indium phosphide) rather thansilica. Furthermore, the transmission characteristics of the tunablemultiplexer/demultiplexer can be varied depending on external controlinput(s).

FIG. 8 illustrates an embodiment of 300C—an electronic subsystem todrive 660A—the on-demand optical add-drop subsystem, integrated with100A—the fast optical switch (wherein 100A—the fast optical switch isbased on 120—the vanadium dioxide ultra-thin-film activated by anelectrical pulse).

In FIG. 8, 240 denotes the external controller, 260 denotes themicroprocessor/field programmable gate array and 280C denotes a driveelectronics unit/module for 660A—the on-demand optical add-dropsubsystem, integrated with 100A—the fast optical switch (wherein100A—the fast optical switch is based on 120—the vanadium dioxideultra-thin-film activated by an electrical pulse).

300C—the electronic subsystem integrates 240, 260 and 280C. 300C—theelectronic subsystem to drive 660A.

240—the external controller can communicate serially with 260—themicroprocessor/field programmable gate array.

FIG. 9 illustrates an embodiment of 680A—an optical network processorsystem, comprising 660A—the on-demand optical add-drop subsystem in amatrix configuration, wherein 660A—the on-demand optical add-dropsubsystem comprises 100A—the fast optical switch is based on 120—thevanadium dioxide ultra-thin-film activated by an electrical pulse justto induce an insulator-to-metal phase transition in 120—the vanadiumdioxide ultra-thin-film.

In FIG. 9, 680A denotes an optical network processor system A; 200Adenotes the optical waveguide; 320 denotes the input single-mode opticalfiber array; 300C denotes the electronic subsystem to drive 660A—theon-demand optical add-drop subsystem; 340 denotes the thermoelectriccooler to maintain 680A—the optical network processor system A at aspecified temperature; 360 denotes the heat sink and 380 denotes theoutput single-mode optical fiber array.

Thus, 680A—the optical network processor system A, demultiplex,multiplex can switch a wavelength from any input fiber to any outputfiber.

FIG. 10 illustrates 660B—an on-demand optical add-drop subsystem,integrated with 100B—the fast optical switch (wherein 100B—the fastoptical switch is based on 120—the vanadium dioxide ultra-thin-filmactivated by a light pulse).

In FIG. 10 , all input wavelengths from 320—the input optical fiber canbe transmitted via 200A—an optical waveguide and amplified by 500—theerbium doped waveguide amplifier integrated with a 980-nm pump laser,tapped by 520—the tap coupler to measure wavelengths by 540—thespectrophotometer. A few wavelengths can proceed to 560A/560B/560C—thefirst wavelength demultiplexer 1 and then exit to the drop ports. Otherexpress wavelengths can proceed to 560A/560B/560C—the second wavelengthdemultiplexer 2 for demultiplexing, then as selective inputs to 100B—thefast optical switch.

An array of rapidly wavelength tunable lasers can provide a set of newwavelengths to the add ports. The output (wavelengths) of560A/560B/560C—the second wavelength demultiplexer 2 and these newlyadded wavelengths can be switched by an array of 100Bs—the fast opticalswitches.

Switched wavelengths from 100Bs—the fast optical switches can bemodulated by an array of 580 s—the optical modulators.

The optical power output of 580—the optical modulator can be controlledby 500—the erbium doped waveguide amplifier integrated with a 980-nmpump laser, 600—the variable optical attenuator and 620—the photodiode.

The modulated wavelengths (or modulated optical signals) can beindependently controlled at a specified optical power and thenmultiplexed by 640A/640B/640C—the multiplexer. Thus, independent controlof each wavelength can enable an approximately flat optical power curvefor all output wavelengths at 380—the output optical fiber.

FIG. 11 illustrates an embodiment of 300D—an electronic subsystem todrive 660B—the on-demand optical add-drop subsystem, integrated with100B—the fast optical switch (wherein 100B—the fast optical switch isbased on 120—the vanadium dioxide ultra-thin-film activated by a lightpulse).

In FIG. 11, 240 denotes the external controller, 260 denotes themicroprocessor/field programmable gate array and 280D denotes a driveelectronics unit/module for 660B—the on-demand optical add-dropsubsystem, integrated with 100B—the fast optical switch (wherein100B—the fast optical switch is based on 120—the vanadium dioxideultra-thin-film activated by a light pulse).

300D—the electronic subsystem integrates 240, 260 and 280D. 300D—theelectronic subsystem is to drive 660B.

240—the external controller can communicate serially with 260—themicroprocessor/field programmable gate array.

FIG. 12 illustrates an embodiment of 680B—an optical network processorsystem B, comprising 660B—the on-demand optical add-drop subsystem in amatrix configuration, wherein 660B—the on-demand optical add-dropsubsystem comprises 100B—the fast optical switch is based on 120—thevanadium dioxide ultra-thin-film activated by a light pulse just toinduce an insulator-to-metal phase transition in 120—the vanadiumdioxide ultra-thin-film.

In FIG. 12, 680B denotes the optical network processor system B; 200Adenotes the optical waveguide; 320 denotes the input single-mode opticalfiber array; 300D denotes the electronic subsystem to drive 660B—theon-demand optical add-drop subsystem; 340 denotes the thermoelectriccooler to maintain; 680B—the optical network processor system B at aspecified temperature; 360 denotes the heat sink and 380 denotes theoutput single-mode optical fiber array.

Thus, 680B—the optical network processor system B, demultiplex,multiplex can switch a wavelength from any input fiber to any outputfiber.

FIG. 13A illustrates 820A—an embodiment of a wavelength converter,wherein 760—a coupler connects to 700—an input optical signal and 720—apump laser via 740—a coupler waveguide. 760—the coupler is opticallycoupled with 780A—As₂S₃ chalcogenide, a four-wave mixing non-linearmaterial. The output of 780A—As₂S₃ chalcogenide, a four-wave mixingnon-linear material, can be optically coupled with 800—a specific filterblock. The output of 800—the filter block is the converted wavelength.

FIG. 13B illustrates 820B—an embodiment of a wavelength converter,wherein 760—a coupler connects to 700—an input optical signal and 720—apump laser via 740—a coupler waveguide. 760—the coupler is opticallycoupled with 780B—two-dimensional photonic crystal-based As₂S₃chalcogenide, a four-wave mixing non-linear material. The output of780B—two-dimensional photonic crystal-based As₂S₃ chalcogenide, afour-wave mixing non-linear material, can be optically coupled with800—the specific filter block. The output of 800—the filter block is theconverted wavelength.

FIG. 13C illustrates 820C—an embodiment of a wavelength converter,wherein 760—a coupler connects to 700—an input optical signal and 720—apump laser via 740—a coupler waveguide. 760—the coupler is opticallycoupled with 780C—graphene on two-dimensional photonic crystal siliconoptical waveguide, a four-wave mixing non-linear material. The output of780C—graphene on two-dimensional photonic crystal silicon opticalwaveguide, a four-wave mixing non-linear material, can be opticallycoupled with 800—the specific filter block. The output of 800—the filterblock is the converted wavelength.

Alternatively, a wavelength converter can be fabricated/constructedutilizing a semiconductor optical amplifier or a quantum dot-basedsemiconductor optical amplifier (QD-SOA).

FIG. 14 illustrates 840A—an on-demand optical add-drop subsystem,integrated with 100A—the fast optical switch (wherein 100A—the fastoptical switch is based on 120 the vanadium dioxide ultra-thin-filmactivated by an electrical pulse) and 820A/B/C—the wavelength converter.

In FIG. 14 , all input wavelengths from 320—the input optical fiber canbe transmitted via 200A—an optical waveguide and amplified by 500—theerbium doped waveguide amplifier integrated with a 980-nm pump laser,tapped by 520—the tap coupler to measure wavelengths by 540—thespectrophotometer. A few wavelengths can proceed to 560A/560B/560C—thefirst wavelength demultiplexer 1 and then exit-to the drop ports. Otherexpress wavelengths can proceed to 560A/560B/560C—the second wavelengthdemultiplexer 2 for demultiplexing, then as selective inputs to 100A—thefast optical switch.

An array of rapidly wavelength tunable lasers can provide a set of newwavelengths to the add ports. The output (wavelengths) of560A/560B/560C—the second wavelength demultiplexer 2 can converted inwavelength by an array of 820A/B/Cs—the wavelength converters. Thus, theconverted wavelengths from the array 820A/B/Cs—the wavelength convertersand these newly added wavelengths can be switched by an array of100As—the fast optical switches.

Switched wavelengths from 100As—the fast optical switches can bemodulated by an array of 580 s—the optical modulators. 580—the opticalmodulator can include a (wafer bonded) nanoscaled modulator of lithiumniobate.

The optical power output of 580—the optical modulator can be controlledby 500—the erbium doped waveguide amplifier integrated with a 980-nmpump laser, 600—the variable optical attenuator and 620—the photodiode.

The modulated wavelengths (or modulated optical signals) can beindependently controlled at a specified optical power and thenmultiplexed by 640A/640B/640C—the multiplexer. Thus, independent controlof each wavelength can enable approximately flat optical power curve forall output wavelengths at 380—the output optical fiber.

FIG. 15 illustrates an embodiment of 300E—an electronic subsystem todrive 840A—the on-demand optical add-drop subsystem, integrated with100A—the fast optical switch (wherein 100A—the fast optical switch isbased on 120—the vanadium dioxide ultra-thin-film activated by anelectrical pulse) and 820A/B/C—the wavelength converter.

In FIG. 15, 240 denotes the external controller, 260 denotes themicroprocessor/field programmable gate array and 280E denotes a driveelectronics unit/module for 840A—the on-demand optical add-dropsubsystem, integrated with 100A—the fast optical switch (wherein100A—the fast optical switch is based on 120—the vanadium dioxideultra-thin-film activated by an electrical pulse) and 820A/B/C—thewavelength converter.

300E—the electronic subsystem integrates 240, 260 and 280E. 300E—theelectronic subsystem to drive 840A.

240—the external controller can communicate serially with 260—themicroprocessor/field programmable gate array.

FIG. 16 illustrates an embodiment of 860A—an advanced optical networkprocessor system C in a matrix configuration, wherein 860A—the advancedoptical network processor system C comprising—840A—the on-demand opticaladd-drop subsystem, wherein 840A—the on-demand optical add-dropsubsystem comprises (a) 100A—the fast optical switch based on 120—thevanadium dioxide ultra-thin-film activated by an electrical pulse justto induce an insulator-to-metal phase transition in 120—the vanadiumdioxide ultra-thin-film and (b) 820A/B/C—the wavelength converter.

In FIG. 16, 860A denotes the advanced optical network processor systemC; 200A denotes the optical waveguide; 320 denotes the input single-modeoptical fiber array; 300E denotes the electronic subsystem to drive840A—the advanced optical network processor system C; 340 denotes thethermoelectric cooler to maintain 860A—the advanced optical networkprocessor system C at a specified temperature; 360 denotes the heat sinkand 380 denotes the output single-mode optical fiber array.

Thus, 860A—the advanced optical network processor system C candemultiplex, multiplex, convert and switch a wavelength from any inputfiber to any output fiber.

FIG. 17 illustrates 840B—an on-demand optical add-drop subsystem,integrated with 100B—the fast optical switch (wherein 100B—the fastoptical switch is based on 120—the vanadium dioxide ultra-thin-filmactivated by a light pulse) and 820A/B/C—the wavelength converter.

In FIG. 17 , all input wavelengths from 320—the input optical fiber canbe transmitted via 200A—an optical waveguide and amplified by 500—theerbium doped waveguide amplifier integrated with a 980-nm pump laser,tapped by 520—the tap coupler to measure wavelengths by 540—thespectrophotometer. A few wavelengths can proceed to 560A/560B/560C—thefirst wavelength demultiplexer 1 and then exit to the drop ports. Otherexpress wavelengths can proceed to 560A/560B/560C—the second wavelengthdemultiplexer 2 for demultiplexing, then as selective inputs to 100B—thefast optical switch.

An array of rapidly wavelength tunable lasers can provide a set of newwavelengths to the add ports. The output (wavelengths) of560A/560B/560C—the second wavelength demultiplexer 2 can be converted inwavelength by an array of 820A/B/Cs—the wavelength converters. Thus, theconverted wavelengths from the array 820A/B/Cs—the wavelength convertersand these newly added wavelengths can be switched by an array of100Bs—the fast optical switches.

Switched wavelengths from 100Bs—the fast optical switches can bemodulated by an array of 580 s—the optical modulators. 580—the opticalmodulator can include a (wafer bonded) nanoscaled modulator of lithiumniobate.

The optical power output of 580—the optical modulator can be controlledby 500—the erbium doped waveguide amplifier integrated with a 980-nmpump laser, 600—the variable optical attenuator and 620—the photodiode.

The modulated wavelengths (or modulated optical signals) can beindependently controlled at a specified optical power and thenmultiplexed by 640A/640B/640C—the multiplexer. Thus, independent controlof each wavelength can enable an approximately flat optical power curvefor all output the wavelengths at 380—the output optical fiber.

FIG. 18 illustrates an embodiment of 300F—an electronic subsystem todrive 840B—the on-demand optical add-drop subsystem, integrated with100B—the fast optical switch (wherein 100B—the fast optical switch isbased on 120—the vanadium dioxide ultra-thin-film activated by a lightpulse) and 820A/B/C—the wavelength converter.

In FIG. 18, 240 denotes the external controller, 260 denotes themicroprocessor/field programmable gate array and 280F denotes a driveelectronics unit/module for 840B—the on-demand optical add-dropsubsystem, integrated with 100B—the fast optical switch (wherein100B—the fast optical switch is based on 120—the vanadium dioxideultra-thin-film activated by a light pulse) and 820A/B/C—the wavelengthconverter.

300F—the electronic subsystem integrates 240, 260 and 280F. 300F—theelectronic subsystem is to drive 840B.

240—the external controller can communicate serially with 260—themicroprocessor/field programmable gate array.

FIG. 19 illustrates an embodiment of 860B—an advanced optical networkprocessor system D in a matrix configuration, wherein 860B—the advancedoptical network processor system D comprising-840B—the on-demand opticaladd-drop subsystem, wherein 840B—the on-demand optical add-dropsubsystem comprises (a) 100B—the fast optical switch is based on 120—thevanadium dioxide ultra-thin-film activated by a light pulse just toinduce an insulator-to-metal transition in 120—the vanadium dioxideultra-thin-film, and (b) 820A/B/C—the wavelength converter.

In FIG. 19, 860B denotes the advanced optical network processor systemD; 200A denotes the optical waveguide; 320 denotes the input single-modeoptical fiber array; 300F denotes the electronic subsystem to drive840B—the advanced optical network processor system D; 340 denotes thethermoelectric cooler to maintain 860B—the advanced optical networkprocessor system D at a specified temperature; 360 denotes the heat sinkand 380 denotes the output single-mode optical fiber array.

Thus, 860B—the advanced optical network processor system D candemultiplex, multiplex, convert and switch a wavelength from any inputfiber to any output fiber.

100A/100B can be integrated with a semiconductor laser/widely tunablesemiconductor laser/widely tunable fast switching semiconductor laser at180A—the input optical waveguide and/or at 180B—the input opticalwaveguide for higher functionality. Such integration can includecoupling from an optical waveguide to another optical waveguide via acollimating lens, wherein the collimating lens can be suitablypositioned by a microelectro-mechanical system(MEMS)/nanoelectro-mechanical system (NEMS) based actuator.

100A/100B can be integrated with an array of semiconductor lasers/widelytunable semiconductor lasers/widely tunable fast switching semiconductorlasers at 180A—the input optical waveguide and/or at 180B—the inputoptical waveguide for higher functionality. Such integration can includecoupling of the array of semiconductor lasers/widely tunablesemiconductor lasers/widely tunable fast switching semiconductor lasersto 180A—the input optical waveguide and/or at 180B—the input opticalwaveguide via a microelectromechanical system/nanoelectromechanicalsystem-based tilt mirror.

400A, 400B, 680A, 680B, 860A and 860B can be integrated with microringresonator filters and/or wavelength tunable optical dispersioncompensators.

Furthermore, 400A, 400B, 680A, 680B, 860A and 860B can be integratedwith biplexer filters and/or triplexer filters.

400A or 400B can be integrated with a log₂ N demultiplexer for opticalpacket switched optical networks, where the switching delay is criticalfor high performance. A log₂ N demultiplexer can consist ofrectangular-shaped periodic frequency filters connected in series,wherein the rectangular-shaped periodic frequency filters can be formedin a one-dimensional photonic crystal structure on a ridge opticalwaveguide.

Flip-chip bonding was developed as an alternative to wire bonding. Inflip-chip bonding, components are flipped upside-down and placed on anarray of solder bumps that form the connection between a device andcircuit. 400A, 400B, 680A, 680B, 860A and 860B can be packaged utilizingflip-chip bonding onto a precise silicon-on-insulator substrate.

Single-mode optical fibers can be aligned passively with precise metalalignment pins seated into v-grooves on the precise substrate. Theprecise metal alignment pins can be utilized top mate with a pluggableoptical fiber connector integrated with a molded plastic lens.Alternatively, an array of multi-mode optical fibers can be used insteadof an array of single-mode optical fibers for short distance (e.g., LAN)applications.

In general, but not limited to the optical switch of a phase transitionmaterial can be: (a) An optical switch including a first opticalwaveguide and a second optical waveguide, wherein the first opticalwaveguide is less than 5 microns in horizontal width, typically 200nanometers to 1 micron,

wherein the second optical waveguide is less than 5 microns inhorizontal width, typically 200 nanometers to 1 micron,

wherein the horizontal width of the first optical waveguide can be sameor different with respect to the second optical waveguide,

wherein the vertical height/thickness/depth of the first opticalwaveguide can be same or different with respect to the second opticalwaveguide, wherein a section of the first optical waveguide issubstantially parallel within manufacturing tolerance to a section ofthe second optical waveguide,wherein the section of the first optical waveguide is optically coupledwith an ultra thin-film of vertical height/thickness/depth less than 0.5microns, typically 50 nanometers to 300 nanometers,wherein the ultra thin-film includes a phase transition material,wherein the phase transition material on the first optical waveguide isreceiving a first stimulant, just to induce insulator-to-metal (IMT)phase transition in the phase transition material on the first opticalwaveguide,wherein the said insulator-to-metal (IMT) phase transition is with achange in lattice structure or without a change in lattice structure,and/orwherein the section of the second optical waveguide is optically coupledwith an ultra thin-film of vertical height/thickness/depth less than 0.5microns, typically 50 nanometers to 300 nanometers,wherein the ultra thin-film includes the phase transition material,wherein the phase transition material on the second optical waveguide isreceiving a second stimulant, just to induce insulator-to-metal (IMT)phase transition in the phase transition material on the second opticalwaveguide,wherein the said insulator-to-metal (IMT) phase transition is with achange in lattice structure or without a change in lattice structure.

The first stimulant is just one of the following: a first electricalpulse or a first light pulse or a first pulse in terahertz (THz)frequency of a suitable field strength or first hot electrons,

or

the first stimulant is the combination of one or more of the following:a first electrical pulse, a first light pulse, a first pulse interahertz (THz) frequency of a suitable field strength and first hotelectrons, wherein the first electrical pulse is a voltage pulse or acurrent pulse.Similarly,The second stimulant is just one of the following: a second electricalpulse or a second light pulse or a second pulse in terahertz (THz)frequency of a suitable field strength or second hot electrons,orthe second stimulant is the combination of one or more of the following:a second electrical pulse, a second light pulse, a second pulse interahertz (THz) frequency of a suitable field strength and second hotelectrons, wherein the second electrical pulse is a voltage pulse or acurrent pulse. (b) Alternatively, an optical switch of a phasetransition material including a first optical waveguide, a secondoptical waveguide and a third waveguide,wherein the first optical waveguide is less than 5 microns in horizontalwidth, typically 200 nanometers to 1 micron,wherein the second optical waveguide is less than 5 microns inhorizontal width, typically 200 nanometers to 1 micron,wherein the third optical waveguide is less than 5 microns in horizontalwidth, typically 200 nanometers to 1 micron,wherein the horizontal width of the first optical waveguide can be sameor different with respect to the horizontal width of the second opticalwaveguide,wherein the horizontal width of the second optical waveguide can be sameor different with respect to the horizontal width of the third opticalwaveguide,wherein the vertical height/thickness/depth of the first opticalwaveguide can be same or different with respect to the second opticalwaveguide,wherein the vertical height/thickness/depth of the second opticalwaveguide can be same or different with respect to the third opticalwaveguide,wherein a section of the first optical waveguide is substantiallyparallel within manufacturing tolerance to a section of the secondoptical waveguide,wherein a section of the second optical waveguide is substantiallyparallel within manufacturing tolerance to a section of the thirdoptical waveguide,wherein the section of the second optical waveguide is optically coupledwith an ultra thin-film of vertical height/thickness/depth less than 0.5microns, typically 50 nanometers to 300 nanometers,wherein the ultra thin-film on the second optical waveguide includes aphase transition material, wherein the phase transition material on thesecond optical waveguide is receiving a stimulant, just to induceinsulator-to-metal (IMT) phase transition in the phase transitionmaterial on the second optical waveguide,wherein the said insulator-to-metal (IMT) phase transition is with achange in lattice structure or without a change in lattice structure.The stimulant is just one of the following: an electrical pulse or alight pulse or a pulse in terahertz (THz) frequency of a suitable fieldstrength or hot electrons,orthe stimulant is the combination of one or more of the following: aelectrical pulse, a light pulse, a pulse in terahertz (THz) frequency ofa suitable field strength and hot electrons, wherein the electricalpulse is a voltage pulse or a current pulse.

The optical switch as in above, wherein the first optical waveguideand/or the second optical waveguide and/or the third optical waveguideis coupled with a one-dimensional photonic crystal.

The optical switch as in above, wherein the first optical waveguideand/or the second optical waveguide and/or the third optical waveguideis coupled with a two-dimensional photonic crystal.

The optical switch as in above, wherein the phase transition material issegmented, wherein each segment has a separate electrical biaselectrode.

The optical switch as in above, wherein the phase transition material isstoichiometric undoped vanadium dioxide or doped vanadium dioxide.

The optical switch as in above, wherein just the phase transitionmaterial is fabricated on a (low optical loss) waveguide material ofinsulator/semiconductor (e.g. diamond or silicon).

The optical switch as in above, wherein the phase transition material isa Mott insulator.

The optical switch as in above, includes gratings of phase transitionmaterials.

The optical switch as in above, further including directionally coupledoptical waveguides or a multimode interference coupler (or aMach-Zehnder interferometer only in the case of the first opticalwaveguide and second optical waveguide).

The optical switch as in above, further including coupling with awavelength multiplexer or a wavelength demultiplexer.

The optical switch as in above, further including coupling with awavelength tunable multiplexer or a wavelength tunable demultiplexer.

The optical switch as in above, further including coupling with awavelength tunable photonic crystal multiplexer or a wavelength tunablephotonic crystal demultiplexer.

The optical switch as in above, further including coupling with anoptical add-drop subsystem or an optical filter.

The optical switch as in above, further including coupling with a ringresonator or a laser.

The optical switch as in above, further including coupling with awavelength converter, wherein the wavelength converter includes As₂S₃chalcogenide material or two-dimensional photonic crystal As₂S₃chalcogenide material or graphene on two-dimensional photonic crystalsilicon optical waveguide. The optical switch, further including thewavelength converter, wherein the wavelength converter also includes asemiconductor optical amplifier or a quantum dot based semiconductoroptical amplifier.

The optical switch according as in above, further including couplingwith a semiconductor optical amplifier or a quantum dot basedsemiconductor optical amplifier or an erbium doped waveguide amplifier.

The optical switch as in above, further including coupling with ananoscaled modulator of lithium niobate.

The optical switch as in above, further including coupling with a lightslowing component or a light stopping component, wherein the lightslowing component or the light stopping component includes metamaterialsof negative refractive index or nanostructures.

The optical switch as in above, includes gradually tapered waveguide forwaveguide to optical fiber coupling.

The optical switch as in above, includes vertically coupled gratings forwaveguide to optical fiber coupling.

The optical switch as in above is flip-chip mounted on a nanoscaled finarray and/or a heat dissipating substrate, wherein the nanoscaled finarray includes an array of nanoscaled metal pillars embedded in athermally conducting thin-film.

The optical switch as in above, is temperature controlled by athermoelectric cooler.

In general, but not limited to the optical switch of a phase changematerial can be:

(a) An optical switch including a first optical waveguide and a secondoptical waveguide, wherein the first optical waveguide is less than 5microns in horizontal width, typically 200 nanometers to 1 micron,

wherein the second optical waveguide is less than 5 microns inhorizontal width, typically 200 nanometers to 1 micron,

wherein the horizontal width of the first optical waveguide can be sameor different with respect to the horizontal width of the second opticalwaveguide,

wherein the vertical height/thickness/depth of the first opticalwaveguide can be same or different with respect to the verticalheight/thickness/depth second optical waveguide,

wherein a section of the first optical waveguide is substantiallyparallel within manufacturing tolerance to a section of the secondoptical waveguide,

wherein the section of the first optical waveguide is optically coupledwith an ultra thin-film of vertical height/thickness/depth less than 0.5microns, less than 0.5 microns, typically 50 nanometers to 400nanometers,

wherein the ultra thin-film includes a phase change material,

wherein the phase change material on the first optical waveguide isreceiving a first stimulant, just to induce phase change in the phasechange material on the first optical waveguide, and/or,

wherein the section of the second optical waveguide is optically coupledwith an ultra thin-film of vertical height/thickness/depth less than 0.5microns, typically 50 nanometers to 400 nanometers,

wherein the ultra thin-film comprises: the phase change material,

wherein the phase change material on the second optical waveguide isreceiving a second stimulant, just to induce phase change in the phasechange material on the second optical waveguide.

The first stimulant is just one of the following: a first electricalpulse or a first light pulse or a first pulse in terahertz (THz)frequency of a suitable field strength,

or

the first stimulant is the combination of one or more of the following:a first electrical pulse, a first light pulse and a first pulse interahertz (THz) frequency of a suitable field strength, wherein thefirst electrical pulse is a voltage pulse or a current pulse.Similarly,The second stimulant is just one of the following: a second electricalpulse or a second light pulse or a second pulse in terahertz (THz)frequency of a suitable field strength,orthe second stimulant is the combination of one or more of the following:a second electrical pulse, a second light pulse and a second pulse interahertz (THz) frequency of a suitable field strength, wherein thesecond electrical pulse is a voltage pulse or a current pulse.(b) Alternatively, an optical switch of a phase change materialincluding a first optical waveguide, a second optical waveguide and athird waveguide,wherein the first optical waveguide is less than 5 microns in horizontalwidth, typically 200 nanometers to 1 micron,wherein the second optical waveguide is less than 5 microns inhorizontal width, typically 200 nanometers to 1 micron,wherein the third optical waveguide is less than 5 microns in horizontalwidth, typically 200 nanometers to 1 micron,wherein the horizontal width of the first optical waveguide can be sameor different with respect to the horizontal width of the second opticalwaveguide,wherein the horizontal width of the second optical waveguide can be sameor different with respect to the horizontal width of the third opticalwaveguide,wherein the vertical height/thickness/depth of the first opticalwaveguide can be same or different with respect to the second opticalwaveguide,wherein the vertical height/thickness/depth of the second opticalwaveguide can be same or different with respect to the third opticalwaveguide,wherein a section of the first optical waveguide is substantiallyparallel within manufacturing tolerance to a section of the secondoptical waveguide,wherein a section of the second optical waveguide is substantiallyparallel within manufacturing tolerance to a section of the thirdoptical waveguide,wherein the section of the second optical waveguide is optically coupledwith an ultra thin-film of vertical height/thickness/depth less than 0.5microns, typically 50 nanometers to 400 nanometers,wherein the ultra thin-film on the second optical waveguide includes aphase change material,wherein the phase transition material on the second optical waveguide isreceiving a stimulant, just to induce phase change in the phase changematerial on the second optical waveguide,The stimulant is just one of the following: an electrical pulse or alight pulse or a pulse in terahertz (THz) frequency of a suitable fieldstrength,orthe stimulant is the combination of one or more of the following: aelectrical pulse, a light pulse and a pulse in terahertz (THz) frequencyof a suitable field strength, wherein the electrical pulse is a voltagepulse or a current pulse.

The optical switch as in above, wherein the first optical waveguideand/or the second optical waveguide and/or the third optical waveguideis coupled with a one-dimensional photonic crystal.

The optical switch as in above, wherein the first optical waveguideand/or the second optical waveguide and/or the third optical waveguideis coupled with a two-dimensional photonic crystal.

The optical switch as in above, wherein the phase change material issegmented, wherein each segment has a separate electrical biaselectrode.

The optical switch as in above, includes gratings of phase changematerials.

The optical switch as in above, wherein the phase transition materialincludes gratings.

The optical switch as in above, further including directionally coupledoptical waveguides or a multimode interference coupler (or aMach-Zehnder interferometer only in the case of the first opticalwaveguide and second optical waveguide).

The optical switch as in above, further including coupling with awavelength multiplexer or a wavelength demultiplexer.

The optical switch as in above, further including coupling with awavelength tunable multiplexer or a wavelength tunable demultiplexer.

The optical switch as in above, further including coupling with awavelength tunable photonic crystal multiplexer or a wavelength tunablephotonic crystal demultiplexer.

The optical switch as in above, further including coupling with anoptical add-drop subsystem or an optical filter.

The optical switch as in above, further including coupling with a ringresonator or a laser.

The optical switch as in above, further including coupling with awavelength converter, wherein the wavelength converter includes As₂S₃chalcogenide material or two-dimensional photonic crystal As₂S₃chalcogenide material or graphene on two-dimensional photonic crystalsilicon optical waveguide. The optical switch, further including thewavelength converter, wherein the wavelength converter also includes asemiconductor optical amplifier or a quantum dot based semiconductoroptical amplifier.

The optical switch according as in above, further including couplingwith a semiconductor optical amplifier or a quantum dot basedsemiconductor optical amplifier or an erbium doped waveguide amplifier.

The optical switch as in above, further including coupling with ananoscaled modulator of lithium niobate.

The optical switch as in above, further including coupling with a lightslowing component or a light stopping component, wherein the lightslowing component or the light stopping component includes metamaterialsof negative refractive index or nanostructures.

The optical switch as in above, includes gradually tapered waveguide forwaveguide to optical fiber coupling.

The optical switch as in above, includes vertically coupled gratings forwaveguide to optical fiber coupling.

The optical switch as in above is flip-chip mounted on a nanoscaled finarray and/or a heat dissipating substrate, wherein the nanoscaled finarray includes an array of nanoscaled metal pillars embedded in athermally conducting thin-film.

The optical switch as in above is temperature controlled by athermoelectric cooler.

It should be noted that the optical switch including a phase transitionmaterial can be faster than the optical switch including a phase changematerial. However, a phase change material may enable lower opticalloss.

PREFERRED EMBODIMENTS & SCOPE OF THE INVENTION

In the above disclosed specifications “/” has been used to indicate an“or” and real-time means near real-time in practice.

In the above disclosed specifications “waveguide” has been used toindicate an “optical waveguide”

As used in this patent application and in the claims, the singular forms“a”, “an”, and “the” include also the plural forms, unless the contextclearly dictates otherwise.

The term “includes” means “comprises”. The term “including” means“comprising”.

The term “couples” or “coupled” does not exclude the presence of anintermediate element(s) between the coupled items.

Any example in the above disclosed specifications is by way of anexample only and not by way of any limitation. Having described andillustrated the principles of the disclosed technology with reference tothe illustrated embodiments, it will be recognized that the illustratedembodiments can be modified in any arrangement and detail with departingfrom such principles. The technologies from any example can be combinedin any arrangement with the technologies described in any one or more ofthe other examples. Alternatives specifically addressed in this patentapplication are merely exemplary and do not constitute all possibleexamples. Claimed invention is disclosed as one of several possibilitiesor as useful separately or in various combinations. See Novozymes A/S v.DuPont Nutrition Biosciences APS, 723 F3d 1336,1347.

The best mode requirement “requires an inventor(s) to disclose the bestmode contemplated by him/her, as of the time he/she executes the patentapplication, of carrying out the invention.” “ . . . [T]he existence ofa best mode is a purely subjective matter depending upon what theinventor(s) actually believed at the time the (patent) application wasfiled.” See Bayer AG v. Schein Pharmaceuticals, Inc. The best moderequirement still exists under the America Invents Act (AIA). At thetime of the invention, the inventor(s) described preferred best modeembodiments of the present invention. The sole purpose of the best moderequirement is to restrain the inventor(s) from applying for a patent,while at the same time concealing from the public preferred embodimentsof their inventions, which they have in fact conceived. The best modeinquiry focuses on the inventor(s)' state of mind at the time he/shefiled the patent application, raising a subjective factual question. Thespecificity of disclosure required to comply with the best moderequirement must be determined by the knowledge of facts within thepossession of the inventor(s) at the time of filing the patentapplication. See Glaxo, Inc. v. Novopharm Ltd., 52 F,3d 1043, 1050 (Fed.Cir. 1995).

The above disclosed specifications are the preferred best modeembodiments of the present invention. However, they are not intended tobe limited only to the preferred best mode embodiments of the presentinvention. Numerous variations and/or modifications are possible withinthe scope of the present invention. Accordingly, the disclosed preferredbest mode embodiments are to be construed as illustrative only. Thosewho are skilled in the art can make various variations and/ormodifications without departing from the scope and spirit of thisinvention. It should be apparent that features of one embodiment can becombined with one or more features of another embodiment to form aplurality of embodiments. The inventor(s) of the present invention isnot required to describe each and every conceivable and possible futureembodiment in the preferred best mode embodiments of the presentinvention. See SRI Int'l v. Matsushita Elec. Corp. of America, 775F.2d1107, 1121, 227 U.S.P.Q. (BNA) 577, 585 (Fed. Cir. 1985) (enbanc).

The scope and spirit of this invention shall be defined by the claimsand the equivalents of the claims only. The exclusive use of allvariations and/or modifications within the scope of the claims isreserved. The general presumption is that claim terms should beinterpreted using their plain and ordinary meaning. See Oxford ImmunotecLtd. v. Qiagen, Inc. et al., Action No. 15-cv-13124-NMG. Unless a claimterm is specifically defined in the preferred best mode embodiments,then a claim term has an ordinary meaning, as understood by a personwith an ordinary skill in the art, at the time of the present invention.Plain claim language will not be narrowed, unless the inventor(s) of thepresent invention clearly and explicitly disclaims broader claim scope.See Sumitomo Dainippon Pharma Co. v. Emcure Pharm. Ltd., Case Nos.17-1798; -1799; -1800 (Fed. Cir. Apr. 16, 2018) (Stoll, J). As notedlong ago: “Specifications teach. Claims claim”. See Rexnord Corp. v.Laitram Corp., 274 F.3d 1336, 1344 (Fed. Cir. 2001). The rights ofclaims (and rights of the equivalents of the claims) under the Doctrineof Equivalents-meeting the “Triple Identity Test” (a) performingsubstantially the same function, (b) in substantially the same way and(c) yielding substantially the same result. See Crown Packaging Tech.,Inc. v. Rexam Beverage Can Co., 559 F.3d 1308, 1312 (Fed. Cir. 2009)) ofthe present invention are not narrowed or limited by the selectiveimports of the specifications (of the preferred embodiments of thepresent invention) into the claims.

While “absolute precision is unattainable” in patented claims, thedefiniteness requirement “mandates clarity.” See Nautilus, Inc. v.Biosig Instruments, Inc., 527 U.S. 898, 134 S. Ct. 2120, 2129, 110USPQ2d 1688, 1693 (2014). Definiteness of claim language must beanalyzed NOT in a vacuum, but in light of:

-   -   (a) The content of the particular patent application disclosure,    -   (b) The teachings of any prior art, and    -   (c) The claim interpretation that would be given by one        possessing the ordinary level of skill in the pertinent art at        the time the invention was made. (Id.).        See Orthokinetics, Inc. v. Safety Travel Chairs, Inc., 806 F.2d        1565, 1 USPQ2d 1081 (Fed. Cir. 1986)

There are number of ways the written description requirement issatisfied.

Applicant(s) does not need to describe every claim element exactly,because there is no such requirement (MPEP § 2163). Rather to satisfythe written description requirement, all that is required is “reasonableclarity” (MPEP § 2163.02). An adequate description may be made in anywaythrough express, implicit or even inherent disclosures in the patentapplication, including word, structures, figures, diagrams and/orequations (MPEP §§ 2163(1), 2163.02). The set of claims in thisinvention generally covers a set of sufficient number of embodiments toconform to written description and enablement doctrine. See AriadPharm., Inc. v. Eli Lilly & Co., 598 F.3d 1336, 1355 (Fed. Cir. 2010),Regents of the University of California v. Eli Lilly & Co., 119 F.3d1559 (Fed. Cir. 1997) & Amgen Inc. v. Chugai Pharmaceutical Co. 927 F.2d1200 (Fed. Cir. 1991).

Furthermore, Amgen Inc. v. Chugai Pharmaceutical Co. exemplifies FederalCircuit's strict enablement requirements. Additionally, the set ofclaims in this invention is intended to inform the scope of thisinvention with “reasonable certainty”. See Interval Licensing, LLC v.AOL Inc. (Fed. Cir. Sep. 10, 2014). A key aspect of the enablementrequirement is that it only requires that others will not have toperform “undue experimentation” to reproduce it. Enablement is notprecluded by the necessity of some experimentation, “[t]he key word is‘undue’, not experimentation.” Enablement is generally considered to bethe most important factor for determining the scope of claim protectionallowed. The scope of enablement must be commensurate with the scope ofthe claims. However, enablement does not require that an inventordisclose every possible embodiment of his invention. The scope ofenablement must be commensurate with the scope of the claims. The scopeof the claims must be less than or equal to the scope of enablement. SeePromega v. Life Technologies Fed. Cir., December 2014, Magsil v. HitachiGlobal Storage Fed. Cir. August 2012.

The term “means” was not used nor intended nor implied in the disclosedpreferred best mode embodiments of the present invention. Thus, theinventor(s) has not limited the scope of the claims as mean plusfunction. An apparatus claim with functional language is not animpermissible “hybrid” claim; instead, it is simply an apparatus claimincluding functional limitations. Additionally, “apparatus claims arenot necessarily indefinite for using functional language . . .[f]unctional language may also be employed to limit the claims withoutusing the means-plus-function format.” See National Presto Industries,Inc. v. The West Bend Co., 76 F. 3d 1185 (Fed. Cir. 1996), R.A.C.C.Indus. v. Stun-Tech, Inc., 178 F.3d 1309 (Fed. Cir. 1998) (unpublished),Microprocessor Enhancement Corp. v. Texas Instruments Inc, & Williamsonv. Citrix Online, LLC, 792 F.3d 1339 (2015).

We claim:
 1. An optical switch comprising: a first optical waveguide anda second optical waveguide, wherein the first optical waveguide is lessthan 5 microns in horizontal width, wherein the second optical waveguideis less than 5 microns in horizontal width, wherein a section of thefirst optical waveguide is substantially parallel within manufacturingtolerance to a section of the second optical waveguide, wherein thesection of the first optical waveguide is optically coupled with anultra thin-film of a vertical thickness or a vertical depth less than0.5 microns, wherein the ultra thin-film comprises: a phase transitionmaterial, wherein the phase transition material on the first opticalwaveguide is receiving a first stimulant, just to induceinsulator-to-metal (IMT) phase transition in the phase transitionmaterial on the first optical waveguide, wherein the saidinsulator-to-metal (IMT) phase transition is with a change in latticestructure or without a change in lattice structure, and/or, wherein thesection of the second optical waveguide is optically coupled with theultra thin-film of a vertical thickness or a vertical depth less than0.5 microns, wherein the ultra thin-film comprises: the phase transitionmaterial, wherein the phase transition material on the second opticalwaveguide is receiving a second stimulant, just to induceinsulator-to-metal (IMT) phase transition in the phase transitionmaterial on the second optical waveguide, and wherein the saidinsulator-to-metal (IMT) phase transition is with a change in latticestructure or without a change in lattice structure; and wherein theoptical switch is flip-chip mounted on a nanoscaled fin array and/or aheat dissipating substrate, wherein the nanoscaled fin array comprisesan array of nanoscaled metal pillars embedded in a thermally conductingthin-film.
 2. An optical switch comprising: a first optical waveguide, asecond optical waveguide and a third waveguide, wherein the firstoptical waveguide is less than 5 microns in horizontal width, whereinthe second optical waveguide is less than 5 microns in horizontal width,wherein the third optical waveguide is less than 5 microns in horizontalwidth, wherein a section of the first optical waveguide is substantiallyparallel within manufacturing tolerance to a section of the secondoptical waveguide, wherein a section of the second optical waveguide issubstantially parallel within manufacturing tolerance to a section ofthe third optical waveguide, wherein the section of the second opticalwaveguide is optically coupled with an ultra thin-film of a verticalthickness or a vertical depth less than 0.5 microns, wherein the ultrathin-film on the second optical waveguide comprises: a phase transitionmaterial, wherein the phase transition material on the second opticalwaveguide is receiving a stimulant, just to induce insulator-to-metal(IMT) phase transition in the phase transition material on the secondoptical waveguide, wherein the said insulator-to-metal (IMT) phasetransition is with a change in lattice structure or without a change inlattice structure, and wherein the optical switch is flip-chip mountedon a nanoscaled fin array and/or a heat dissipating substrate, andwherein the nanoscaled fin array comprises an array of nanoscaled metalpillars embedded in a thermally conducting thin-film.